The present invention relates to computer memory systems, and more specifically, to multi-match error detection in content addressable memory testing.
In some computer systems, content addressable memory is used where memory locations are addressed based on contents rather than an encoded physical address. In a content addressable memory (CAM) device, a CAM section is used to identify a corresponding location in a random access memory (RAM) section that holds a data value, where each CAM section row has a corresponding RAM section row. Search and compare logic can be used to locate CAM section entries and return corresponding RAM section entries. The inclusion of a CAM device in a computer system design increases testing complexity due to potential mismatches and/or multiple matches of the search and compare logic. For example, to verify proper operation of the CAM device, it must be shown that a desired CAM row can be located on a content match and further that one or more other CAM rows are not also selected for the same content match (referred to as a multi-match error). When only summarized test results of attempted read operations are available, it can be difficult to ensure that multi-match errors are detected.